U.S. patent number 11,441,693 [Application Number 16/444,479] was granted by the patent office on 2022-09-13 for manual override assembly.
This patent grant is currently assigned to Danfoss Power Solutions II Technology A/S. The grantee listed for this patent is DANFOSS POWER SOLUTIONS II TECHNOLOGY A/S. Invention is credited to Tam Chi Huynh.
United States Patent |
11,441,693 |
Huynh |
September 13, 2022 |
Manual override assembly
Abstract
A manual override assembly for a hydraulic power source operates
to override an actuator of a hydraulic power source. The assembly
includes a lever arm and connecting rods. The lever arm pivotally
moves relative to a valve body of the hydraulic power source. The
lever arm is connected to valve spools via the connecting rods,
respectively. Each spool has a bore with an off-set opening for
inserting one end of the connecting rod.
Inventors: |
Huynh; Tam Chi (Richfield,
MN) |
Applicant: |
Name |
City |
State |
Country |
Type |
DANFOSS POWER SOLUTIONS II TECHNOLOGY A/S |
Nordborg |
N/A |
DK |
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Assignee: |
Danfoss Power Solutions II
Technology A/S (N/A)
|
Family
ID: |
1000006555205 |
Appl.
No.: |
16/444,479 |
Filed: |
June 18, 2019 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20190301629 A1 |
Oct 3, 2019 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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15307678 |
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10371276 |
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PCT/US2015/028279 |
Apr 29, 2015 |
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61987188 |
May 1, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16K
31/60 (20130101); F15B 13/10 (20130101); F16K
11/07 (20130101); F15B 13/0814 (20130101); F16K
31/05 (20130101); F15B 13/0402 (20130101); F16K
11/0708 (20130101); Y10T 137/87209 (20150401); F15B
2211/895 (20130101); F15B 2211/862 (20130101); F15B
2211/863 (20130101); Y10T 137/87193 (20150401) |
Current International
Class: |
F15B
13/10 (20060101); F16K 31/05 (20060101); F15B
13/08 (20060101); F16K 11/07 (20060101); F15B
13/04 (20060101); F16K 31/60 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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201486951 |
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May 2010 |
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201486951 |
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May 2010 |
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CN |
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101994728 |
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Mar 2011 |
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CN |
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101994728 |
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Mar 2011 |
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CN |
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201953735 |
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Aug 2011 |
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CN |
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201953735 |
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Aug 2011 |
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CN |
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202501041 |
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Oct 2012 |
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CN |
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202501041 |
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Oct 2012 |
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CN |
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3810273 |
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Oct 1989 |
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DE |
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3810273 |
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Oct 1989 |
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DE |
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2 061 386 |
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May 1981 |
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GB |
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2 061 386 |
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May 1981 |
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GB |
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Other References
International Search Report and Written Opinion of the
International Searching Authority for International Patent
Application No. PCT/US2015/028279 dated Jul. 21, 2015, 8 pgs.
imported from a related application .
Extended European Search Report for corresponding European Patent
Application No. 15785581.8 dated Apr. 24, 2018, 9 pages. imported
from a related application .
Extended European Search Report for Application No. 19191564.4
dated Nov. 26, 2019. cited by applicant.
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Primary Examiner: Jellett; Matthew W
Assistant Examiner: Ballman; Christopher D
Attorney, Agent or Firm: Merchant & Gould P.C.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION(S)
This application is a division of U.S. patent application Ser. No.
15/307,678, filed on Oct. 28, 2016, which is a U.S. National Stage
of PCT/US2015/028279, filed on Apr. 29, 2015, which claims benefit
of U.S. Patent Application Ser. No. 61/987,188 filed on May 1,
2014, and which applications are incorporated herein by reference.
To the extent appropriate, a claim of priority is made to each of
the above disclosed applications.
Claims
What is claimed is:
1. A spool valve connection arrangement comprising: a connecting
rod including a rod retention element adjacent a first end of the
connecting rod; and a valve spool defining a spool axis and
including lands and at least one recess between the lands, the
valve spool also defining an internal connecting rod bore
positioned adjacent one end of the valve spool, the valve spool
further including an axial end face at the end of the valve spool,
the axial end face defining a bore access opening having a
cross-sectional profile perpendicular to the spool axis that is
fully enclosed when viewed from the axial end face, the bore access
opening including a first region and a second region, the first
region and the second region being positioned along the same plane
as the axial end face perpendicular to the spool axis, the second
region being laterally offset perpendicular to the spool axis from
the first region, the second region of the bore access opening
being co-extensive with the connecting rod bore and the first
region being at least partially laterally offset from the
connecting rod bore, the first region of the bore access opening
being sized and shaped to allow the first end of the connecting rod
including the rod retention element to be inserted therethrough
parallel to the spool axis, the second region of the bore access
opening being sized and shaped to prevent the first end of the
connecting rod including the retention element from being axially
withdrawn from the connecting rod bore, wherein the connecting rod
is coupled to the end of the spool by inserting the first end of
the connecting rod including the rod retention element through the
first region of the bore access opening and then moving the
connecting rod perpendicularly to the spool axis from the first
region of the bore access opening into the second region of the
bore access opening.
2. The spool valve connection arrangement of claim 1, wherein the
second region of the bore access opening includes a lip that
opposes the rod retention element to prevent the connecting rod
from being axially removed from the connecting rod bore when the
connecting rod is positioned to extend through the second region of
the bore access opening.
3. The spool valve connection arrangement of claim 2, wherein the
first end of the connecting rod is captured within the connecting
rod bore and wherein a limited first range of axial movement is
permitted between the spool and the connecting rod.
4. The spool valve connection arrangement of claim 3, wherein the
connecting rod is connected to a manual actuator for manually
adjusting an axial position of the spool within a spool bore
defined by a valve body.
5. The spool valve connection arrangement of claim 4, further
comprising a powered actuator for axially moving the spool within
the spool bore, wherein when the manual actuator is in a neutral
position, movement of the spool by the powered actuator does not
cause movement of the connecting rod.
6. The spool valve connection arrangement of claim 4, wherein the
manual actuator can move the connecting rod axially though a second
range of movement that is longer than the first range of axial
movement.
7. A method for coupling a connecting rod to a valve spool defining
a spool axis, the connecting rod including a rod retention element
adjacent a first end of the connecting rod, the valve spool
including lands and at least one recess between the lands, the
valve spool also defining an internal connecting rod bore
positioned adjacent one end of the valve spool, the valve spool
further including an axial end face at the end of the valve spool,
the axial end face defining a bore access opening having a
cross-sectional profile perpendicular to the spool axis that is
fully enclosed when viewed from the axial end face, the bore access
opening including a first region and a second region, the first
region and the second region being positioned along the same plane
as the axial end face perpendicular to the spool axis, the second
region being laterally offset perpendicular to the spool axis from
the first region, the first region of the bore access opening being
sized and shaped to allow the first end of the connecting rod
including the rod retention element to be inserted therethrough
parallel to the spool axis, the second region of the bore access
opening being sized and shaped to prevent the first end of the
connecting rod including the retention element from being withdrawn
from the connecting rod bore, the valve spool mounting within a
spool bore of a valve body, the method comprising: inserting, in a
direction parallel to the spool axis, the first end of the
connecting rod including the rod retention element through the
first region of the bore access opening; moving, in a direction
perpendicular to the spool axis, the connecting rod from the first
region of the bore access opening into the second region of the
bore access opening; and retaining the connecting rod in alignment,
parallel to the spool axis, with the second region of the bore
access opening while the valve spool is mounted in the spool bore
of the valve body by mounting the connecting rod relative to the
valve body at a location where an axis of the connecting rod passes
through the second region of the bore access opening.
Description
FIELD
The present disclosure relates to a manual override assembly that
can be installed in a hydraulic power system. The present
disclosure further relates to a spool and a retainer plug of the
manual override assembly.
BACKGROUND
Twin spool valve assemblies are used in hydraulic power systems for
controlling hydraulic fluid flow to work components such as
hydraulic cylinders. A twin spool valve assembly can include first
and second spools that are moved within corresponding spool bores
of the valve assembly to alternatingly place corresponding first
and second work ports of the of the valve assembly in fluid
communication with either pump system pressure or tank pressure. In
operation, a powered actuator (e.g., a solenoid arrangement, voice
coil arrangement, pilot valve arrangement, etc.) can coordinate
movement of the first and second spools within their corresponding
spool bores such that when the first work port is in fluid
communication with pump system pressure, the second work port is in
fluid communication with tank pressure, and when the first work
port is in fluid communication with tank pressure, the second pork
port is in fluid communication with pump system pressure. The first
and second work ports can be respectively coupled to first and
second ports of a work component such that pump system pressure
from the hydraulic power system can be used to drive movement of
the work component.
US 2013/0048893 discloses an example twin spool valve assembly
having a manual override for allowing the positions of the twin
spools to be manually adjusted in the event of failure of the
powered actuator. In this way, movement of the corresponding work
component can be manually controlled in situations where the
powered actuator is not operational.
Existing manual overrides can be subject to wear and can be
relatively complicated in design (i.e., can include a relatively
large number of separate parts that need to be assembled) thereby
increasing manufacturing and installation costs. It would be
beneficial to provide for a spool assembly and retainer plug
assembly comprising fewer parts than the currently available
assemblies. It would further be beneficial to provide for a spool
assembly and retainer plug assembly that are more cost effective to
manufacture and easier to assemble.
SUMMARY
The present disclosure relates to a hydraulic power source
comprising a valve body defining a first spool bore and a second
spool bore; a first spool disposed in the first spool bore and a
second spool disposed in the second spool bore; an actuator for
alternatingly moving the spools in a first direction and a second
direction that is opposite of the first direction so that when one
spool moves in the first direction, the other spool moves in the
second direction; and a manual override assembly for overriding the
actuator. The manual override assembly includes a lever arm
pivotally movable relative to the valve body about a pivot axis,
and a first connecting rod for connecting the lever arm to the
first spool and a second connecting rod for connecting the lever
arm to the second spool. The first and second connecting rods each
include a spool engagement flange. The first and second connecting
rods are connected to the lever arm on opposite sides of the pivot
axis, wherein when the lever arm is pivoted about the pivot axis in
a clockwise direction the first connecting rod is moved in the
first direction and the second connecting rod is moved in the
second direction, and when the lever is pivoted in a
counterclockwise direction the first connecting rod is moved in the
second direction and the second connecting rod is moved in the
first direction. The first and second spools each include
connecting rod bores for respectively receiving the first and
second connecting rods. The first and second spools further include
axial end faces that define bore access openings for providing
access to the connecting rod bores, the bore access openings each
including a first region and a second region laterally offset from
the first region, the first regions being sized and shaped to allow
insertion of the spool engagement flanges of the connecting rods
therethrough, the second regions being sized and shaped to prevent
the spool engagement flanges from passing therethrough. The first
and second connecting rods are loaded into their respective
connecting rod bores and thereby coupled with their corresponding
first and second spools by inserting the spool engagement flanges
through the first regions of the bore access openings and then
sliding the connecting rods laterally into alignment with the
second regions of the bore access openings such that the spool
engagement flanges are captured within the spool bores.
The present disclosure further relates to a spool valve connection
arrangement comprising a connecting rod including a rod retention
element adjacent a first end of the connecting rod, and a valve
spool including lands and at least one recess between the lands.
The valve spool also defines an internal connecting rod bore
positioned adjacent one end of the valve spool, where the valve
spool includes an axial end face at the end of the valve spool, the
axial end face defining a bore access opening including a first
region and a second region laterally offset from the first region.
The second region of the bore access opening is co-extensive with
the connecting rod bore and the first region is at least partially
laterally offset from the connecting rod bore. The first region of
the bore access opening is sized and shaped to allow the first end
of the connecting rod including rod retention element to be
inserted therethrough. The second region of the bore access opening
is sized and shaped to prevent the first end of the connecting rod
including the retention element from being axially withdrawn from
the connecting rod bore. The connecting rod is coupled to the end
of the spool by inserting the first end of the connecting rod
including the rod retention element through the first region of the
bore access opening and then moving the connecting rod laterally
from the first region of the connecting rod opening into the second
region of the bore access opening.
The present disclosure further relates to a method for coupling a
connecting rod to a valve spool. The connecting rod includes a rod
retention element adjacent a first end of the connecting rod. The
valve spool includes lands and at least one recess between the
lands, the valve spool also defining an internal connecting rod
bore positioned adjacent one end of the valve spool. The valve
spool further includes an axial end face at the end of the valve
spool, the axial end face defining a bore access opening including
a first region and a second region laterally offset from the first
region, the first region of the bore access opening being sized and
shaped to allow the first end of the connecting rod including rod
retention element to be inserted therethrough, the second region of
the bore access opening being sized and shaped to prevent the first
end of the connecting rod including the retention element from
being withdrawn from the connecting rod bore. The valve spool is
mounted within a spool bore of a valve body. The method comprises
the steps of inserting the first end of the connecting rod
including the rod retention element through the first region of the
bore access opening; moving the connecting rod laterally from the
first region of the connecting rod opening into the second region
of the bore access opening; and retaining the connecting rod in
alignment with the second region of the bore access opening while
the valve spool is mounted in spool bore of the valve body by
mounting the connecting rod relative to the valve body at a
location where an axis of the connecting rod passes through the
second region of the bore access opening.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 shows a cross sectional view of a hydraulic power source
with a manual override assembly according to an example of the
present disclosure.
FIG. 2A shows the manual override assembly of the hydraulic power
source of FIG. 1 in a neutral position.
FIG. 2B shows the manual override assembly of the hydraulic power
source of FIG. 1 in a first override position.
FIG. 2C shows the manual override assembly of the hydraulic power
source of FIG. 1 in a second override position.
FIG. 3A shows a cross sectional view of the manual override
assembly of FIG. 1.
FIG. 3B shows a bottom perspective view of the manual override
assembly of FIG. 1.
FIG. 4A shows a perspective view of a spool of the manual override
assembly of FIG. 1.
FIG. 4B shows a side view of the spool of FIG. 4A.
FIG. 4C shows a perspective view of the spool of FIG. 4A.
FIG. 4D shows a bottom view of the spool of FIG. 4A.
FIG. 4E shows a cross sectional view of the spool of FIG. 4A.
FIG. 4F shows a cross sectional view of the spool of FIG. 4A with a
connecting rod.
FIG. 4G shows a cross sectional view of the spool of FIG. 4A with a
piston assembly.
FIG. 4H shows a top view of the spool of FIG. 4A.
FIG. 5A shows a cross sectional view of a retainer plug assembly of
the hydraulic power source of FIG. 1.
FIG. 5B shows a connecting rod of the hydraulic power source of
FIG. 1.
FIG. 5C is an exploded view of the retainer plug assembly and
connecting rod of the hydraulic power source of FIG. 1.
FIG. 6A shows a partial cross sectional view of the spool and
connecting rod of the hydraulic power source of FIG. 1.
FIG. 6B shows a partial cross sectional view of the connecting rod
of the hydraulic power source of FIG. 1.
FIG. 7 shows a perspective view of a manifold of hydraulic power
sources of FIG. 1.
DETAILED DESCRIPTION
The present disclosure relates to a manual override assembly. The
manual override assembly can be installed on a hydraulic power
source or another system in need of manual override capability,
such as a system having an electronically controlled valve
system.
FIG. 1 shows an example of a hydraulic power source 100 with a
manual override assembly 1 according to the present disclosure.
During normal operation the hydraulic power source 100 is operated
by a powered actuator 102 (e.g., a pilot valve, a solenoid
arrangement, a voice coil arrangement, etc.). The hydraulic power
source 100 comprises a valve body 101 defining a first spool bore
110 and a second spool bore 110'. The hydraulic power source 100
includes work ports 104, 104'. Hydraulic fluid flow through work
ports 104, 104' is controlled by two spools 10 (shown as a first
spool 10 and second spool 10') disposed in spool bores 110, 110'.
In one example, the powered actuator 102 selectively directs
hydraulic fluid under pilot pressure to chambers 81, 81', 84, or
84' that causes upward or downward movement of the spools 10, 10'.
Movement of the spools 10, 10' provides alternating fluid
communication between a high pressure gallery 112, 112' and the
work ports 104, 104', and between the work ports 104, 104' and a
low pressure gallery 111, 111'. The terms "up," "upward," "down,"
and "downward" are used here indicating directions relative to a
longitudinal spool axis A10 (see FIG. 4E) when the spools are in a
vertical position, but the hydraulic power source 100 and the
manual override assembly 1 could, of course, exist in any
directional position in the three-dimensional space.
The high pressure galleries 112, 112' connect to a high pressure
side of a pump that provides system pressure to the high pressure
galleries 112, 112'. Conventional load control technology can be
used to control the system pressure provided to the high pressure
galleries 112, 112' by the pump. The low pressure galleries 111,
111' connect to a tank or reservoir at tank pressure.
According to the present disclosure, the spools 10, 10' function as
three-position spool valves that can be in a neutral position
(shown in FIG. 1), an upper position, or a lower position. Springs
82, 82' bias the spools 10, 10' into the neutral position when the
spools 10, 10' are not actuated by the actuator 102 or the manual
override assembly 1. When a spool (e.g., either of the spools 10,
10') is actuated into the lower position, a flow path from the pump
and the high pressure gallery 112 to the work port 104 is created.
When a spool (either of the spools 10, 10') is actuated into the
upper position, a flow path through the work port 104 and the low
pressure gallery 111 to the tank is created.
In a first phase of operation the actuator 102 controls the first
spool 10 to move downward as the second spool 10' simultaneously
moves upward. When the first spool 10 moves down by an operating
distance to the lower position, a flow path (e.g., a path defined
by a groove of the spool 10) between the high pressure gallery 112
and the work port 104 is created, allowing flow of hydraulic fluid
from the high pressure gallery 112, through the work port 104 and
line 140, into the first chamber 201 of a work component 200 (e.g.,
hydraulic cylinder), according to one example. The increased
pressure and fluid volume in the first chamber 201 causes a
movement of a piston 203, further causing flow of hydraulic fluid
from the second chamber 202 through line 140', into the second work
port 104'. The upward movement of the second spool 10' to the upper
position creates a flow path (e.g., defined by a groove of the
spool 10') between the second work port 104' and the low pressure
gallery 111', allowing the hydraulic fluid to flow from the work
port into tank. In a second phase of operation the flow is reversed
as the second spool 10' moves to the lower position and the first
spool 10 moves to the upper position.
Occasionally it may be desirable to operate the hydraulic power
source 100 manually using a manual override assembly 1. The manual
override assembly 1 mechanically interfaces with the spools 10, 10'
and includes: two retainer plug assemblies 20, connecting rods 30,
and a lever assembly 40. In manual operation as shown in FIGS.
2A-2C, the lever 41 can be manually pivoted up or down, to manually
adjust the positions of the spools 10, 10' via the connecting rods
30, 30'. FIG. 2A shows the lever 41 in a neutral resting position
(e.g., in a horizontal position). The lever 41 is mounted on a
valve body 101 of the hydraulic power source 100 by a mounting
bracket 44 and a pin 45.
The pin 45 creates a pivot axis 46 for the lever 41 so that when a
proximal end 411 (e.g., a handle portion) of the lever 41 is pushed
up, as shown in FIG. 2B, the lever 41 pivots counterclockwise
around the pin 45, causing a distal end 412 of the lever 41 to move
downward. The pivoting movement of the lever 41 causes the first
connecting rod 30 to move upward and to engage the first spool 10,
pushing the spool 10 upward and opening a flow path between the
first work port 104 and the first low pressure gallery 111. The
downward movement of the distal end 412 pulls down the second
connecting rod 30' coupled with the distal end 412. The second
connecting rod 30' in turn engages and pulls down the second spool
10' that the second connecting rod 30' is coupled with, opening a
flow path between the high pressure gallery 112' and the second
work port 104'.
When the proximal end 411 of the lever 41 is pushed down, as shown
in FIG. 2C, the lever 41 pivots clockwise about the pivot pin 45
and pulls down the first connecting rod 30 that is coupled with the
lever 41 on the proximal side of the pin 45 and pushes up the
second connecting rod 30' on the distal side of the pin 45. As the
lever pivots clockwise, the first connecting rod 30 engages and
pulls down the first spool 10 toward the lower position and the
second connecting rod 30' moves simultaneously upward, engaging and
pushing up the second spool 10' toward the upper position. The
retainer plug assemblies 20, 20' are mounted on the valve body 101
of the hydraulic power source 100 and remain in a stationary
position during operation.
FIG. 3A shows a cross sectional view of the manual override
assembly 1 according to an example of the present disclosure. One
end of the connecting rods 30, 30' engages with the spools 10, 10'
(respectively), and the other end of the connecting rods 30, 30'
couples with the lever 41, connecting the spools 10, 10' to the
lever 41. The connecting rods 30, 30' extend through and are
axially centered within the retainer plugs 21, 21'. The lever 41
has two openings 42 with a narrowing section 43 that engages a ball
end 33, 33' of the connecting rods 30, 30' by a neck 34, 34'. FIG.
3B shows a bottom perspective view of the manual override assembly
1.
FIGS. 4A-4H show various views of the spool 10 according to an
example of the present disclosure. The spool 10 comprises a first
end 11 and a second end 15 and a plurality of recesses 18 (i.e.,
grooves) axially disposed along the length of the spool 10. The
spacing of the recesses 18 is configured to permit flow between the
high pressure gallery 112 and the work port 104, or between the
work port 104 and the low pressure gallery 111 when the spool 10 is
moved from its neutral resting position by a minimum operating
distance MD10. The recesses 18 are separated by rings 19 (also
referred to as lands), the diameter of which closely matches the
inside diameter of the spool bore 110. The rings 19 may comprise a
plurality of recesses 191 circumferentially disposed around the
perimeter of the ring 19. When the spool 10 is in a resting
position the rings 19 engage with the inside surface of the spool
bore 110, preventing flow between the high pressure gallery 112,
the low pressure gallery 111, and the work port 104. It will be
appreciated that the spool 10' has the same configuration.
Referring now to FIGS. 4C-4G, according to an example of the
present disclosure, the spool 10 comprises a longitudinal spool
axis A10 and at the first end 11 of the spool 10 a connecting rod
bore 12 having a bore axis A12. The connecting rod bore 12
comprises an end opening 120 (i.e., a bore access opening) at an
axial end face 115 of the spool 10 with an insertion region 121 for
inserting the connecting rod 30 into the connecting rod bore 12,
the insertion region 121 having an insertion axis A121, and a
retention region 122 through which the connecting rod 30 extends in
an assembled position, the retention region 122 having a retention
axis A122. The retention axis A122, the spool axis A10, and the
bore axis A12 are co-axially aligned with one another, whereas the
insertion axis A121 is laterally offset from the spool axis A10 by
a distance W121. The first and second connecting rods 30, 30' are
loaded into their respective connecting rod bores 12, 12' and
thereby coupled with their corresponding first and second spools
10, 10' by inserting the spool engagement flanges 31, 31' axially
through the insertion regions 121, 121' of the bore access openings
120, 120' and then sliding the connecting rods 30, 30' laterally
into alignment with the retention regions 122, 122' of the bore
access openings 120, 120' such that the spool engagement flanges
31, 31' are captured within the spool bores 12, 12' and the
connection rods 30, 30' extend through the retention regions 122,
122'.
The retention region 122 of the opening 120 has a cross-dimension
including a diameter D122 that is partially defined by a lip 123.
The lip 123 is positioned at an opposite end of the opening 120
from the insertion region 121 and has a width W123. The lip 123
operates to retain a retaining element such as a flange 31 of the
connecting rod 30 inside the connecting rod bore 12 when the manual
override assembly 1 is assembled. The connecting rod bore 12 has a
closed end 124 defining a depth H12. Each connecting rod 30, 30'
comprises a retention element such as a flange 31, 31' that engages
the spool 10, 10' at the lip 123, 123' when the connecting rod 30,
30' is moved downward while the rod 30, 30' is aligned with and
passes through the retention region 122, or at the closed end 124,
124' when the connecting rod 30, 30' is moved upward. The flange 31
has a cross dimension D31 (see FIG. 5B). In one example, the flange
31 is annular and the cross dimension D31 is the diameter of the
flange 31. The connecting rod bore 12 of the spool 10 has a
diameter D12 (see FIG. 4D) that is larger than the cross dimension
D31 of the flange 31.
FIG. 4G shows a spool 10 coupled with parts of the actuator 102 at
the second end 15 of the spool 10. In normal operation the actuator
102 interfaces with a controller that controls the position of the
spool 10 in the spool bore 110. A position sensor 83 is used to
sense the vertical position of the spool 10. The position sensor 83
is seated in a sensor cavity 17 at the bottom of an opening 16 at
the second end 15 of the spool 10. FIG. 4H shows a top view of the
spool 10, showing the opening 16 and the sensor cavity 17. In an
example, the actuator 102 changes the position of the spool 10 by
selectively directing a flow of hydraulic fluid at pilot pressure
into a first chamber 81 or a second chamber 84 (shown in FIG. 1).
The spring 82 biases the spool 10 into a neutral position. It will
be appreciated that position of the spool 10' can be controlled in
the same way by the actuator 102.
FIGS. 5A-5C show the connecting rod 30 and the retainer plug
assembly 20 according to an example of the present disclosure. The
retainer plug assembly 20 comprises a retainer plug 21 (i.e., a
spring housing) having threading 22 that is used to mount the
retainer plug assembly 20 to the valve body 101 of the hydraulic
power source 100. The retainer plug assembly 20 further comprises
seals 23, 24, and a dirt wiper ring 25. When the retainer plug
assembly 20 and the connecting rod 30 are assembled together, the
dirt wiper ring 25 is positioned around the connecting rod 30 and
prevents dirt and debris from getting into the retainer plug
assembly 20 and further into the spool bore 110 where they could
cause excessive wear. The retainer plug assembly 20 comprises a
stopper 28 (e.g., a washer) separating a stop collar 35 (i.e., a
spring compression flange) of the connecting rod 30 from a spring
assembly 29 disposed inside the retainer plug 21. The spring
assembly 29 engages the connecting rod 30 via the stop collar 35
and the stopper 28 and biases the connecting rod 30 to a neutral
position. A retainer such as a snap ring retains the spring
assembly 29 and the stopper 28 in the retainer plug 21 and defines
a stop location that corresponds to the neutral position of the
manual override 1. The spring assembly 29 may comprise one or more
springs (e.g., three coil springs as shown in the FIGURES, where
each of the springs have a different diameter and springs fit
inside one another). Using a plurality of interfitting springs
enables the use of a shorter retainer plug 21.
A threaded port in the valve body 101 receives the retainer plug 21
(see FIG. 1). The threaded port is co-axially aligned with the
corresponding spool bore and spool. When mounted in the threaded
port with the connecting rod 30 supported therein, the retainer
plug assembly 20 maintains the axis A30 of the connecting rod 30 in
co-axial alignment with the spool bore, the connecting rod bore 12
and the retention axis A122 of the retention portion 122 of the end
opening 120 of the spool 10. Thus, when the override assembly 1 is
assembled, the retainer plug assembly 20 prevents the connecting
rod 30 from moving laterally relative to the spool 10 from the
retention portion 122 to the insertion portion 121. In this way,
once the override assembly is assembled, the connecting rod 30 will
not inadvertently de-couple from its corresponding spool 10.
During normal operation when the spools 10, 10' are actuated by the
actuator 102 and when the lever 41 is in a neutral position, the
actuator 102 imparts a limited/controlled range of motion to the
spools 10, 10'. FIG. 6A shows a close-up view of the lower end of
the spool 10 positioned in the spool bore 110 and the upper end of
the connecting rod 30. When the system is in a neutral position,
the flange 31 is axially centered in the connecting rod bore 12. In
order to create a flow path between the high pressure gallery 112
and the work port 104, the spool 10 is moved down a distance b so
that the ring 19 (or the recess 191) clears the edge 113 of the
spool bore 110. Similarly, in order to create a flow path between
the work port 104 and the low pressure gallery 111, the spool 10 is
moved up by a distance a. The range of motion of the spool 10
imparted by the actuator 102 is a+b. In one example a+b is the
maximum axial displacement of the spool 10 permitted by the
actuator 102. The depth H12 of the connecting rod bore 12 defines
the maximum axial distance the spool 10 can move relative to the
connecting rod 30. The depth H12 is configured to be greater than
the range of motion (a+b) of the spool 10 so that, in normal
operation, when the spool 10 is moved by the actuator, the flange
31 does not come into contact with the spool 10 either at the lip
123 or at the closed end 124. This configuration avoids movement of
the connecting rods 30, 30' or the lever 41 as the spools 10, 10'
are moved up or down by the actuator.
During manual operation the connecting rod 30 moves downward and
the flange 31 engages the lip 123 to impart a downward motion to
the spool 10, and when the connecting 30 moves upward, the flange
31 engages the closed end 124 to impart an upward motion to the
spool 10. As shown in FIG. 6B, the range of axial movement provided
to the connection rods 30, 30' by the lever 41 is greater than the
distance H12 between the lips 123, 123' and the closed ends 124,
124'. In one example the range of motion of the connecting rods 30,
30' is H12+a+b.
According to an example, the spool 10 has a one-piece construction
and can be machined from a single block of metal, thus saving in
manufacturing costs and simplifying assembly. According to another
example, the combination of the spool 10 and the retainer plug 21
of the present disclosure enables a more compact design while
preventing movement of the lever 41 when the hydraulic power source
100 is in normal operation. The present design may also provide a
more durable system with fewer leaks.
Multiple hydraulic power sources 100 with manual override systems 1
can be assembled on a manifold, as shown in FIG. 7, such that the
high pressure galleries 112 of the hydraulic power sources 100 are
in fluid communication and are fed by a single high pressure
source, and the low pressure galleries 111 feed into a single fluid
outlet (e.g., a tank).
Various modifications and alterations of this disclosure will
become apparent to those skilled in the art without departing from
the scope and spirit of this disclosure, and it should be
understood that the scope of this disclosure is not to be unduly
limited to the illustrative examples set forth herein.
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